This invention relates to a system for steering beams of radiant energy utilizing a curved array of radiating elements and, more particularly, to a sonar transducer array in which the transducer elements are arranged in a generally cylindrical format.
Sonic and electromagnetic radiation systems employing electronically steerable beams typically utilize a flat surface array of transducers or radiating elements for radiating a steerable beam. While curved arrays for sonar have been disclosed in the prior art, such as, for example, in U.S. Pat. No. 3,370,267 which issued to H. J. Barry on Feb. 20, 1968, and U.S. Pat. No. 3,497,868 which issued to C. H. Lanphier on Feb. 24, 1970, the use of a multiply-tiered array, such as a cylindrical array, has not found wide use in sonar tracking systems employing an electronically steerable beam because of the larger amount of computation required for establishing a set of delay values for delay units coupled to each of the transducer elements for forming a beam in a particular direction. This is a critical problem in the case of systems wherein the beam is to be steered rapidly in both elevation and azimuthal directions, tilt and bearing directions relative to an axis of the array, because the great amount of computer time required for the computation militates against a rapid scanning of the beam. Thus, the advantages of hemispherical coverage or at least a portion of a hemisphere including 360.degree. of azimuthal coverage as can be provided by a cylindrical array, is not available for a rapidly scanning sonar system.